2.2 The Proteome a) The Synthesis and transport of proteins ii Synthesis of membrane components

Question 1

Where are lipids and proteins synthesised?

Answer 1

Endoplasmic reticulum

Question 2

What is the difference between RER and SER?

Answer 2

Rough ER (RER) has ribosomes on its
cytosolic face while smooth ER (SER) lacks
ribosomes.

Question 3

What happens to lipids after they are synthesised in the SER

Answer 3

Lipids are synthesised in the smooth
endoplasmic reticulum (SER) and inserted
into its membrane so it is continually expanding

Question 4

Where does the synthesis of all proteins begin

Answer 4

In cytosolic ribosomes

Question 5

What kind of proteins complete their synthesis in cytosolic ribosomes?

Answer 5

Cytosolic proteins

Question 6

Where do cytosolic proteins go once synthesised?

Answer 6

They remain in the cytosol

Question 7

What is a signal sequence?

Answer 7

A signal sequence is a short stretch of amino
acids at one end of the polypeptide that
determines the eventual location of a protein
in a cell.

Question 8

How does the RER form?

Answer 8

Transmembrane proteins carry a signal
sequence, which halts translation and directs
the ribosome synthesising the protein to dock
with the ER, forming RER

Question 9

What continues after docking?

Answer 9

Translation

Question 10

continues after docking, and the
protein is inserted into the membrane of the
ER

Answer 10

continues after docking, and the
protein is inserted into the membrane of the
ER